Need Help!

[crooked spine]

Hi friends, I'm on my 3rd grow, the two times i veg under t5 but now i decide to on MH, whats the procedure?, my babies r 4 inch tall, should i put my plants under the lights now?if so, whats the distance? my light is 400w MH. Thank so much.:icon_smile:

 

[nematocyte]

MH is a great choice for veg--you won't regret it.

The distance will depend on your ventilation and temperatures, but at four inches tall with everything dialed in, you can figure around 24" or so. If you want your plants more squat and the temps at the top of your plants aren't much above 80, you can go closer. The hand method works great.. if you can hold the sensitive (upper) part of your hand beneath the light at distance of, say, 16" without any discomfort, the plants will be able to handle that distance.

Since you are presumably trying the MH out for the first time, I would err on the side of caution and start higher up with your light. You can always move it down based on your results.

 

[The Hemp Goddess]

Why are you going back to MH? I switched from MH to T5s several years ago and will never go back to MH. I can get the same veggy growth with 216w of T5s that I was getting from 400W of MH and with a whole lot less heat and better light spread.

If you do use your MH, keep them a foot or more away to see how they adjust. How old are they and how many internodes do you have? Height really doesn't tell us much...